The LNF Tuning Guide

[Victory Red SS]

saw that there is going to be an update to this guide. any idea when that will be?

12/21/2012
Oh, wait, that's when the End Of The World is...

[Optimum Motorsports]

Hello all, I've been reading through the various threads on the LNF... there is a lot to read! I have a few questions that I'm looking to get answers to, and hopefully this is the right place for them.

To make a long story short, I'm working on a 2007 Solstice GXP for a customer that wanted me to take a "fresh eyes" look at the tuning. The car currently has a ECU that has Trifecta + a HP tune, and they previously struggled with hitting boost limits despite the Trifecta.

I am new to this platform and have very little experience with HPT, although I have experience with other turbocharged vehicles and software. Much of what I usually work on uses race ECU's that make the process a lot more straightforward, with everything documented so I'm not guessing what does what.

We started with a new ECU with a factory flash, and I'm using the 2.23 Beta. After spending some time reading up on the forums and spending some time with it on the dyno, I have a few things I hoping to get clarified.

Should I be able to log the Boost Solenoid Control and Boost Desired DC on a 2007 Solstice GXP? I see it in logs that other people have posted, but on this car they come up blank. Does it only work on Cobalts?

Can someone explain how the Boost/WG tables work on this car? I understand the usual PID functions. Usually I have a table for WGDC vs. desired boost/RPM, which sets the WG starting point for any boost event. Then each of the PID terms has their Gain Factors, and a Maximum Value for each as an adder to the base table-- but the Proportional Max number seem way to high to be an adder like what I'm used to seeing. I've read on the forums that maybe it's a multiplier? But then shouldn't it have values above 100%?

My understanding was that the Overboost/Underboost functions in 2.23 are supposed to replace what the Trifecta did. Either way, even if I raise the Enable RPM to 9000 I still seem to be able to get it into Overboost mode. The only way I have found to avoid this is to crank up the Overboost Allowed Error, and even at that if the DAL is too low I can still trigger it. Can someone explain how this works? Does the Enable RPM function just not work? Also, since we are running with the MAP pegged, what value is it using for this comparison?

That should be enough to get the converstaion started... any input is appreciated!

[Iam Broke]

You need a newer beta to log the Boost sol and yes, you can log the Lo Res sensor in the charge pipe up to 512 kPa. At WOT they are essentially at the same pressure.

I'll let others address your questions but they have all been answered here before.

[Optimum Motorsports]

Newer Beta? I just got it last week! Is there something else I need to ask for?

I'm sure that much of what I'm asking has been discussed, but there is so much that I can't find it. If there are specific threads I should look at let me know...

Thanks.

[cobaltssoverbooster]

Hello all, I've been reading through the various threads on the LNF... there is a lot to read! I have a few questions that I'm looking to get answers to, and hopefully this is the right place for them.

To make a long story short, I'm working on a 2007 Solstice GXP for a customer that wanted me to take a "fresh eyes" look at the tuning. The car currently has a ECU that has Trifecta + a HP tune, and they previously struggled with hitting boost limits despite the Trifecta.

I am new to this platform and have very little experience with HPT, although I have experience with other turbocharged vehicles and software. Much of what I usually work on uses race ECU's that make the process a lot more straightforward, with everything documented so I'm not guessing what does what.

We started with a new ECU with a factory flash, and I'm using the 2.23 Beta. After spending some time reading up on the forums and spending some time with it on the dyno, I have a few things I hoping to get clarified.

Should I be able to log the Boost Solenoid Control and Boost Desired DC on a 2007 Solstice GXP? I see it in logs that other people have posted, but on this car they come up blank. Does it only work on Cobalts?

Can someone explain how the Boost/WG tables work on this car? I understand the usual PID functions. Usually I have a table for WGDC vs. desired boost/RPM, which sets the WG starting point for any boost event. Then each of the PID terms has their Gain Factors, and a Maximum Value for each as an adder to the base table-- but the Proportional Max number seem way to high to be an adder like what I'm used to seeing. I've read on the forums that maybe it's a multiplier? But then shouldn't it have values above 100%?

My understanding was that the Overboost/Underboost functions in 2.23 are supposed to replace what the Trifecta did. Either way, even if I raise the Enable RPM to 9000 I still seem to be able to get it into Overboost mode. The only way I have found to avoid this is to crank up the Overboost Allowed Error, and even at that if the DAL is too low I can still trigger it. Can someone explain how this works? Does the Enable RPM function just not work? Also, since we are running with the MAP pegged, what value is it using for this comparison?

That should be enough to get the converstaion started... any input is appreciated!

your 2.23 is the latest edition to hpt.....now let the info spew begin
1st for your wg duty cycle you need to add it to the table(primary) in the vcm scanner. it should be listed as "boost desired dc" under the engine airflow section. if its not there then you cant read it.

2nd the desired wg % table is just that, a table that has the value of desired wg dc % for the load x rpm condition. this table is adjusted in conjuction with the desired airload table(dal) to adjust boost levels

3rd if you are trying to prevent overboosting errors or reduction in power over 22.5 psi you need to find a file that has the 2007 solstice gxp stage kit flash in it and transfer all of the turbocharger settings. the only calibration that doesnt get transfer is the map scale settings which are "map sensor linear" and "map sensor offset" same goes for boost sensor[those are changed for the kit supplied 3bar sensors]. that should allow you to boost anything. then for overboost condition the enable is set to maximum allowed value which iirc is 10,200rpm.

the factory map sensor is 2.5 bar and 23 psi is read as 255kpa. this is the limit of the sensor as well as the factory pillar gauge; even with the stage kit the pillar is innacurate past 23psi. this can be faked out with the above statement of taking all turbocharger and map/overboost settings from a stage flash.

turbo gain tables and proportional max: the boys who actually own dyno's and tune lnfs on a regular basis have said there is power to be made there but i dont know how those tables work or what they correspond to. i leave mine with the gmpp stage kit settings.

if you run out of fuel on the top end you will need to adjust the hpf injector window to allow opening sooner than tdc(360) i believe its under homo single low in fuel tab, but i would research that before doing it it could be the homo single high.
hope that helped

[cobaltssoverbooster]

this should help rope your maf in if you didnt find anything yet...
http://www.hptuners.com/forum/showthread.php?t=35129

and courtesy of byt spending alot of time driving in his own vehicle this is by far the best cam news i have read
http://www.hptuners.com/forum/showthread.php?t=34324

[Optimum Motorsports]

1st for your wg duty cycle you need to add it to the table(primary) in the vcm scanner. it should be listed as "boost desired dc" under the engine airflow section. if its not there then you cant read it.

OK, got it. I had just added it to the chart, didn't realize it had to be in table first.

2nd the desired wg % table is just that, a table that has the value of desired wg dc % for the load x rpm condition. this table is adjusted in conjuction with the desired airload table(dal) to adjust boost levels

What is the name of that table? Is it "Duty Cycle Corr"? Seems like an odd name.

3rd if you are trying to prevent overboosting errors or reduction in power over 22.5 psi you need to find a file that has the 2007 solstice gxp stage kit flash in it and transfer all of the turbocharger settings.

When you say the turbocharger settings, you mean everything in Engne > Torque Management > Turbocharger, as well as Engine Diagnostocs > Airflow (except for the MAP)? Just a copy from a stage kit into my existing tune?

the factory map sensor is 2.5 bar and 23 psi is read as 255kpa.

So how does it control boost over 2.5 bar? Does it have some way of inferring pressure based on MAF, or are we just forcing it to go over with the WGDC and setting the overboost settings to ignore it?

Thanks for the input. It's a little clearer now, but it seems like there are still quite a few things that aren'd fully understood.

[Iam Broke]

To measure over 22.4 psi and to control it, you need the 3 BAR sensors and proper sensor data lifted from a GMPP tune. The stock base files work better IMO as there is less turbo nanny built into the tables we cannot see vs. the GMPP ones.

Boosting over 22.4 psi with the 2.5 BAR sensors is running it outside of the control range but can be done. Boost will not track temperature changes as colder dense air will produce higher pressures than warm air so some deviation is expected.


Yes, the Duty Cycle Correction table is one of the tables you seek for dialing it in vs. RPM & Load. You will have to widen out the overboost and underboost settings as well or it will go into limp mode.

Log the Lo Res MAP sensor also, that is the lower CP MAP. The two MAP's will cross around 5psi on most LNF's. Remember the turbo builds some boost even at cruise, the throttle plate is between the two sensors.

[Optimum Motorsports]

OK, let me know if I have this correct:

-Based on pedal position, a torque demand is calculated but we can't see what drives this. We would expect that WOT=100%
-That value then goes through the Max Air Load Torque table and potentially gets truncated to a value lower than 100% at WOT, but we can adjust that table to prevent this from happening.
-The Torque Demand, in %, goes through the DAL table where based on RPM and % Torque, it comes up with the desired load, in unknown units.
-The DAL is then used to calculate a desired throttle opening and boost pressure to achieve that DAL. We can't see the tables that drive this calculation. If we have the DAL cranked up far enough, it will come up with a desired boost that is above the limit of the MAP sensor.
-Since the desired boost is above the range of the sensor, the boost controller doesn't know where it is, and the resulting boost level ends up being based on how we have the WGDC tables set, with no closed loop control. As conditions change, you "get what you get".

That's just a little scary.

Unfortunately I can't use the 3Bar MAP in this application due to racing rules.

[Iam Broke]

Tune it in the coldest climate you are going to run for 24 psi, that's about the safe limit for the ring lands at .88 PE Lambda. As temps rise, boost will fall off and be in the control range.

Max the DAL's at 250 or so and use the DCC table to dial in the WOT in the highest load column. Smooth the DAL's in the last two columns to avoid it being too peaky getting into WOT. You will have to reduce the DCC in the midrange to prevent going over 24 psi. I also reduce the Max torque in 4th & 5th to ~85% to keep it from overboosting there after dialing in third.

You will need to raise the limit to 100% in the tables and let the turbo overspool to hold 19 psi @ 6k or it will fall off rapidly. There is one other table that tapers off up top, but it escapes me now.

[Iam Broke]

The GMPP sensors are factory authorized options, why can't you use them if you can tune the beast in the first place?

[Optimum Motorsports]

The GMPP sensors are factory authorized options, why can't you use them if you can tune the beast in the first place?

I don't write the rules, I'm just stuck with them.

[Optimum Motorsports]

...you can log the Lo Res sensor in the charge pipe up to 512 kPa. At WOT they are essentially at the same pressure.

Still a little confused on this part. There are only 2 sensors, correct? I have 3 different PIDs that I am logging:

MAP
Boost LoRes
Boost Sensor Pressure

As expected MAP doesn't track the other two "Boost" values when the throttle isn't at WOT. The two Boost values track each other within a few KPA. However, MAP tops out at 255kPa, Boost LoRes Tops out at 262kPa, and Boost Sensor Pressure tops out at 207.2kPa. I am logging boost through a standalone sensor and know that I can get it to go above 262kPA and it is obvious from how it flat-lines that it is above that. You said that it is good to 512kPa, but looking at the sensor scaling that isn't possible. Are these just two different PIDs for the same sensor, with one having a lower limit but better resolution? That seems to be the case, as LoRes never shows any decimal values.

One other thing-- am I correct that there has been no solution to the throttle delay? Tried all the settings with no change, and reading on the forum it looks like others have had the same result.

[Iam Broke]

THe lo res sensor is in the lower charge pipe and should max out at 2.5 bar on the stock sensors. MAP is based off of the 2.5 bar sensor in the intake manifold.

2.5 * 14.5 (1 ATM)= 36.25 psi absolute, subtract 1 ATM or ~14.5 for 21.75 psi or so.

The ECU MAP pressure displayed is limited to 255 kPa regardless of the 2.5 or 3 bar sensors. IIRC this is a limit of the ECU. What I meant was the Lo Res (Charge pipe) MAP is capable of displaying up to 512 kPa in the ECU. Even the 3 bar sensor won't range that high though. Prob around 29-30 psi depending on ATM pressure.

I use the MAP - BARO for the PID, then it displays true boost over ATM pressure.

The Lo Res PID will show decimal places depending on how it is configured in your chart, ect.

AFAIK no one has removed the throttle delay. If you try it with the key on, engine not running you will see how fast it can respond. I believe it is a function of the programming no one has hacked yet.

[cobaltssoverbooster]

O.M.-
kinda correct- the "boost desired DC" is the pid for the wg% being used by the ecu.

iambroke is saying the ecu has the internal capability of reading sensor inputs up to 512kpa but the sensors installed cap out at factory 2.5bar=255kpa ~23psi (i believe this ecu was overingineered knowing from the previous lsj models that modification would come and a raised map limit would help greatly with quality of resolution and ease of map swaps.)
if your sensor is flatlining in the scanner you are probably overboosting. so as you have already figured out by now im sure, start with kpa reading under and slowly adjust up until they just barely hit the 255 value.

"boost lo res" is the most accurate sensor to read for boost pressure. take that sensor and subtract the absolute baro sensor(atmospheric baro sensor) for better sensor driven results at wot.

the dal table is not a table of the desired kpa to be run. this is a airflow demand table that modifies boost as a side effect to control the ammount of air entering the engine.
basicaly at wot since the plate is wide open the only thing the ecu knows it can do to get more air is to close the turbo wg/recirc and spool in some extra air...side effect-more boost.
iirc there is also a certain point of pedal position i believe ~ 85-90% the ecu actually commands the etc to wide open and just adjusts the turbo to change airflow demand requirements. (thats the best way i could describe it, although the actual calculation includes many more tables. some of which we have control over)

the throttle response nanny is believed to be living in the bcm which hpt has not agreed to unlock control of yet seeing as it is not a directly engine related controll unit. supposedly the pedal nanny is appart of esc/abs and even though the systems get put in bypass mode she still makes herself present as a factory safety feature??? this is mostly rumors at the moment because no one knows exactly where the delay controls are actualy located at.

[cobaltssoverbooster]

for the hpfp settings are the homo single high low table values a representation of crankshaft rotation in deg* like if i want a sooner open i lower the value? need a tad more fuel up top and i think a few degrees sooner will benefit up there.

[Optimum Motorsports]

the dal table is not a table of the desired kpa to be run. this is a airflow demand table that modifies boost as a side effect to control the ammount of air entering the engine.

I understand that it is a load demand, but somewhere that load demand is correlated to a desired boost level, at least as a starting point. When you first go to WOT, the desired boost PID jumps up to a certain value and it has to wait for the actual pressure to get there. Once it gets close to that value, I would expect that the desired boost is modified based on the load. Note that all of your boost control parameters are pressure based, not load based. So from what I can see, DAL drives the Desired Boost (in tables that we can't see), and the Desired Boost drives the wastegate controller. When the actual load doesn't match the DAL, it calls for more or less Desired Boost, and the wastegate controller responds to that. This is what makes operating above 254kPa such a crapshoot. If the ECU could really change the WGDC directly based on Load it could follow whatever DAL you put in there-- but it can't. So as soon as you use a DAL that pegs the Desired Boost at 254kPa it loses all control of it, and you are basically just using your WGDC parameters to hopefully keep it from going too high.

basicaly at wot since the plate is wide open the only thing the ecu knows it can do to get more air is to close the turbo wg/recirc and spool in some extra air...side effect-more boost.
iirc there is also a certain point of pedal position i believe ~ 85-90% the ecu actually commands the etc to wide open and just adjusts the turbo to change airflow demand requirements. (thats the best way i could describe it, although the actual calculation includes many more tables. some of which we have control over)

I have seen ocassions where the ETC will drop down off of 100% even when the pedal is at 100%. I believe that this occurs when a DAL change is desired that is faster than what can be done with boost changes.

[cobaltssoverbooster]

all sounds correct sir u figured it out. we bassically are overshooting and roping it in with the wg controller.

[altereddezignz]

I know this is an old thread but i have been p[osting everywhere and have yet to get help for the most part. I cannot get the histogram to collect data no matter what i try, No adv timing or KR . But will read in all other cars. 00 cavalier.

[cobaltssoverbooster]

did you connect your scanner to the car and click connect in the software with the ignition to key on engine off?
after that did you add all the required parameters to your table primary like mentioned in the scanner setup video?
after setting histos and plots your data should work at this point, otherwise you are experiencing either a can communication error or software problems.